Brief interventions (BIs) for alcohol use disorders (AUDs) have increased in popularity during the past few decades, and there is a substantial body of research supporting their efficacy and/or effectiveness. With respect to the studies comparing brief interventions with more extensive AUDs treatments {{(i.e., specialist BIs; SBIs),}} the overwhelming majority have yielded non-significant differences, which has been interpreted as showing that specialist BIs and more extensive AUDs treatments do not differ. Findings from research assessment related behavior change studies, however, suggests that the apparent lack of incremental effects for more extensive treatments relative to SBIs may be due in part to reactivity effect biases. In this regard, the research protocols used to compare SBIs with more extensive AUDs treatments typically involved comprehensive assessments administered multiple times across follow-up periods spanning a year or more. Therefore, it may be that the research protocols contributed to Type II error by in effect extending the SBIs, resulting in their becoming indistinguishable in outcomes from the ostensibly more extensive treatments. Thus, it appears that the research methods used to compare SBIs and more extensive AUD treatments introduced a confound that obscured true treatment differences. In addition, there is a paucity of knowledge regarding the mechanisms of behavior change (MoBC) that underlie specialist brief interventions. Given this background, the proposed research has two specific aims: 1) to determine if research assessment protocols influence specialist brief interventions to the extent that they become indistinguishable in outcomes from more extensive AUD treatments; and 2) to investigate the mechanisms of behavior change that underlie specialist brief interventions and research assessment related behavior change. To investigate the application's specific aims, individuals 18 years of age and older with AUD diagnoses will be randomly assigned to one of {{four research conditions: motivational enhancement therapy (MET) with frequent-comprehensive assessment; MET with infrequent-brief assessment; cognitive behavior therapy (CBT) with frequent-comprehensive assessment; or CBT with infrequent-brief assessment.}} The long-term goal of this research is to enhance technology transfer from clinical trials of SBIs to clinical practice. Study results will have implications fo clinical practice as well as for intervention/treatment research methodology.